HOCl retrievals from the Atmospheric Chemistry Experiment

Bernath, Peter F.; Dodandodage, R.; Boone, C. D.; Crouse, Jeff

doi:10.1016/j.jqsrt.2021.107559

Cited by 7 publications

(4 citation statements)

References 27 publications

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“…HOCl is produced from ClO and ClONO 2 . At mid-latitudes the reaction making HOCl ( 20 , 21 ) isClO + HO 2 → HOCl + O 2 The injection of organic molecules into the stratosphere leads to the formation of formaldehyde (H 2 CO) and other sources of HO 2 radicals ( 18 ); H 2 CO near 18 km was observed to be enhanced well into 2021 (fig. S4).…”

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confidence: 99%

Wildfire smoke destroys stratospheric ozone

Bernath

Boone

Crouse

2022

Science

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Large wildfires inject smoke and biomass-burning products into the mid-latitude stratosphere, where they destroy ozone, which protects us from ultraviolet radiation. The infrared spectrometer on the Atmospheric Chemistry Experiment satellite measured the spectra of smoke particles from the “Black Summer” fires in Australia in late 2019 and early 2020, revealing that they contain oxygenated organic functional groups and water adsorption on the surfaces. These injected smoke particles have produced unexpected and extreme perturbations in stratospheric gases beyond any seen in the previous 15 years of measurements, including increases in formaldehyde, chlorine nitrate, chlorine monoxide, and hypochlorous acid and decreases in ozone, nitrogen dioxide, and hydrochloric acid. These perturbations in stratospheric composition have the potential to affect ozone chemistry in unexpected ways.

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confidence: 99%

Wildfire smoke destroys stratospheric ozone

Bernath

Boone

Crouse

2022

Science

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“…Recently, Bernath et al. (2021) reported high values of HOCl up to 1.34 ppb at an altitude of 22.5 km during Antarctic ozone depletion. However, surface HOCl was not reported in their study.…”

Section: Resultsmentioning

confidence: 99%

“…For HOCl, the direct observation from Lawler et al (2011) showed a range from lower than their detection limit of 5-173 ppt in summer tropical Atlantic MBL. Recently, Bernath et al (2021) reported high values of HOCl up to 1.34 ppb at an altitude of 22.5 km during Antarctic ozone depletion. However, surface HOCl was not reported in their study.…”

Section: The Role Of S(iv) + Hox In Summer Arctic Mblmentioning

confidence: 99%

Isotopic Constraints on the Formation Mechanisms of Sulfate Aerosols in the Summer Arctic Marine Boundary Layer

Alexander

Kang

et al. 2022

JGR Atmospheres

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The Arctic climate has warmed rapidly over recent decades with the combined effect of greenhouse gases and aerosols (IPCC, 2013). Sulfate is a major aerosol species offsetting the Arctic warming via scattering of solar radiation and modification of cloud microphysics (Tilgner et al., 2021;Yang et al., 2018). Quantifying the climatic effects of sulfate needs information on its sources, distribution, and formation pathways. Sulfate in the Arctic marine boundary layer (MBL) originates from sea salt, anthropogenic emissions, biogenic and volcanic sources and involves in the oxidation of SO 2 (Ghahremaninezhad et al., 2016;Jiang et al., 2021). The oxidation of SO 2 by OH in the gas phase leads to the formation of H 2 SO 4 (g), which can nucleate new particles and increase the number of cloud condensation nuclei (CCN) (Kulmala et al., 2000). In cloud droplets, the dissolved SO 2 (S(I) is easily oxidized by H 2 O 2 , O 3 , hypohalous acids (HOX = HOCl + HOBr), and transition metal ions (TMI)-catalyzed O 2 in the aqueous phase (Alexander et al., 2009;Chen et al., 2016), contributing to the growth of particles (Lelieveld & Heintzenberg, 1992). The relative importance of these mechanisms can be traced by oxygen-17 excess (Δ 17 O = δ 17 O-0.52δ 18 O) due to the Δ 17 O signature of their oxidants being transferred to sulfate during the oxidation of SO 2 and S(IV). Sulfate formed in the aqueous-phase via O 3 and H 2 O 2 oxidation leads to Δ 17 O(SO 4 2− ) = 9.8‰ and 0.7‰, respectively (Shao et al., 2019), under the assumption of Δ 17 O(O 3 ) = 26‰ (Ishino et al., 2017; Vicars & Savarino, 2014) and Δ 17 O(H 2 O 2 ) = 1.4‰ (Savarino & Thiemens, 1999). Sulfate from other processes result in Δ 17 O(SO 4 2−) = 0‰, including OH oxidation in the gas-phase, HOX and TMI-catalyzed O 2 oxidation in the aqueous phase, anthropogenic primary sulfate and sea-salt sulfate (

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“…A new ACE-FTS processing version (5.0) is underway that will include line-of-sight wind as a standard data product. ACE-FTS version 5.0 will also feature two additional molecules compared to version 4.1 [4], HOCl [5] and CH 2 F 2 (HFC-32), and will extend the VMR retrievals for SO 2 and ClO to higher altitude.…”

Section: Introductionmentioning

confidence: 99%

Line-of-Sight Winds and Doppler Effect Smearing in ACE-FTS Solar Occultation Measurements

et al. 2021

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Line-of-sight wind profiles are derived from Doppler shifts in infrared solar occultation measurements from the Atmospheric Chemistry Experiment Fourier transform spectrometers (ACE-FTS), the primary instrument on SCISAT, a satellite-based mission for monitoring the Earth’s atmosphere. Comparisons suggest a possible eastward bias from 20 m/s to 30 m/s in ACE-FTS results above 80 km relative to some datasets but no persistent bias relative to other datasets. For instruments operating in a limb geometry, looking through a wide range of altitudes, smearing of the Doppler effect along the line of sight can impact the measured signal, particularly for saturated absorption lines. Implications of Doppler effect smearing are investigated for forward model calculations and volume mixing ratio retrievals. Effects are generally small enough to be safely ignored, except for molecules having a large overhang in their volume mixing ratio profile, such as carbon monoxide.

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HOCl retrievals from the Atmospheric Chemistry Experiment

Cited by 7 publications

References 27 publications

Wildfire smoke destroys stratospheric ozone

Wildfire smoke destroys stratospheric ozone

Isotopic Constraints on the Formation Mechanisms of Sulfate Aerosols in the Summer Arctic Marine Boundary Layer

Line-of-Sight Winds and Doppler Effect Smearing in ACE-FTS Solar Occultation Measurements

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